Co/CoSe2 Heterojunction Confined in N, Se co-doped Mesoporous Carbon as Efficient Electrocatalyst for Zn-air battery and Fuel cell

초록

Rechargeable Zn-air batteries (ZABs) and Anion-exchange membrane fuel cells (AEMFCs) have received great attention for their high energy density, and environmental friendliness. However, Oxygen reduction reaction (ORR) and Oxygen evolution reaction (OER) at cathode suffer from sluggish kinetic involving four-electron reaction pathway. However, noble metal-based materials (Pt/C and RuO2) are state-of-the-art electrocatalysts for ORR and OER, their high cost and low stability are challenges for practical applications. Generally, Transition metal chalcogenides (TMCs) have attracted attention as efficient electrocatalysts because of their low cost, electrochemical stability, and great redox properties. Among the various candidates, transition metal selenides have high electrical conductivity from their metallic properties compared with other chalcogenides such as. To boost electrocatalytic ORR, OER activity of metal selenides, construction of heterojunction with metals and semiconductor can be adopted as efficient strategy. Especially, Mott-Schottky heterojunction between metals and n-type metal selenides can further promote charge transfer efficiency of electrocatalyst. Introducing the heteroatoms doping into the carbon skeleton can improve electrocatalytic activity inducing charge redistribution due to different electronegativity. Inspired by above considerations, Co/CoSe2 embedded mesoporous structured with N, Se co-doped mesoporous carbon is synthesized via polymerization and subsequent pyrolysis steps. First, zinc, cobalt based bimetallic ZIF is prepared by coprecipitation, which were used to generate uniform hollow structures. And then, mesostructured polydopamine (mPDA) layers and coated via nano-emulsion strategy on the surface of bimetallic ZIFs by incorporating Pluronic F127 and TMB. Pluronic F127 acts as an agent forming micelles and TMB serves as expanding agent, forming uniform micelles.